1. Field of the Invention
The present invention relates to an audio information processing apparatus and an audio information processing method.
2. Description of the Related Art
Up to now, as an audio system, for example, systems corresponding to multi channels represented by a 5.1 ch surround (Dolby Digital) have been widely used. DOLBY and DOLBY DIGITAL are trademarks of Dolby Laboratories Licensing Corporation, USA.
For example, in a case of a 5.1 ch surround system, speakers corresponding to six-audio channels including a front left channel (FL), a front right channel (FR), a front center channel (FC), a sub woofer channel (SW), a rear left channel (RL), and a rear right channel (RR) are installed at appropriate positions so that an audio with realistic sensation can be output.
On the other hand, in recent years, an electronic device such as a digital camera or a digital video camera has been remarkably developed. In the digital camera or the digital video camera, various recording media such as a magnetic tape, a hard disk drive, a recordable optical disc, and a semiconductor memory are now being used. In particular, along with an increase in capacity of the recording media, large volume data can be recorded therein. Thus, for example, a digital camera or a digital video camera equipped with the 5.1 ch surround system has been proposed.
For example, Japanese Patent Laid-Open No. 2000-299842 discloses a method of generating a multi channel surround audio on the basis of audios collected from a plurality of microphones to record the multi channel surround audio in a video tape or a video disk.
Also, Japanese Patent Laid-Open No. 2005-341073 discloses an apparatus for synthesizing an audio from a rear center channel microphone with audios collected from four front and rear channel microphones by way of addition, subtraction, or the like.
Incidentally, FIG. 11 illustrates a polar pattern of an audio recorded in the video camera for recording 5.1 ch surround audio, for example. The polar pattern has directionality. If the video camera is panned during image pickup, the recorded audio is affected by this panning.
For example, during normal shooting, when the image pickup is performed while viewing an electronic view finder, a positional relation between the camera and a photographer is as illustrated in a schematic diagram of FIG. 12. FIG. 12 illustrates a positional relation between the camera and the photographer in a horizontal plane. At this time, the video camera and a mouth of the photographer have substantially the same relative positional relations. Thus, even when the video camera is panned, the recording is not affected by the panning.
However, when the video camera is placed on a tripod stand and image pickup is performed along with a narration while observing a liquid crystal monitor, the positional relation is established as illustrated in a schematic diagram of FIG. 13. FIG. 13 illustrates a positional relation between the camera and the photographer in a horizontal plane. When the camera is panned with the positional relation illustrated in FIG. 13, a narration audio from the photographer in the rear area who is not appearing in this scene is recorded nonuniformly in left and right sides. As a result, the audio is extremely hard to hear at the time of reproduction with unpleasant sensation.